1. Field of the Invention
Embodiments of the invention relate to providing group call priority access in Long Term Evolution (LTE) and priority access for user equipments (UEs) with dual access classes.
2. Description of the Related Art
Wireless communication systems have developed through various generations, including a first-generation analog wireless phone service (1G), a second-generation (2G) digital wireless phone service (including interim 2.5G and 2.75G networks) and third-generation (3G) and fourth-generation (4G) high speed data/Internet-capable wireless services. There are presently many different types of wireless communication systems in use, including Cellular and Personal Communications Service (PCS) systems. Examples of known cellular systems include the cellular Analog Advanced Mobile Phone System (AMPS), and digital cellular systems based on Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), the Global System for Mobile access (GSM) variation of TDMA, and newer hybrid digital communication systems using both TDMA and CDMA technologies.
More recently, Long Term Evolution (LTE) has been developed as a wireless communications protocol for wireless communication of high-speed data for mobile phones and other data terminals. LTE is based on GSM, and includes contributions from various GSM-related protocols such as Enhanced Data rates for GSM Evolution (EDGE), and Universal Mobile Telecommunications System (UMTS) protocols such as High-Speed Packet Access (HSPA).
A cellular system may support broadcast, multicast, and unicast services. A broadcast service is a service that may be received by all users, e.g., news broadcast. A multicast service is a service that may be received by a group of users, e.g., a subscription video service. A unicast service is a service intended for a specific user, e.g., voice call. Group communications can be implemented using either unicast, broadcast, multicast or a combination of each. As the group becomes larger it is generally more efficient to use multicast services.
Certain cellular systems offer group priority access, thereby improving the chance of high priority group members being able to access the network by reducing the access channel collision. This is achieved by preventing other low priority users from performing channel access procedures when a select high priority group call is placed.
LTE networks support access barring by broadcasting the class(es) or categories of subscribers barred from network access on a cell-by-cell basis, as indicated in the system information block (SIB) message. UEs are provisioned with one or more access classes, and if at least one access class on the UE is permitted access based on the SIB message, the UE is allowed to perform access attempts. The typical use of access class-based barring is to categorize users into two ranges: the range that is barred from access and the remaining set that is allowed access.